ALEXANDER GERST / AFP
According to projections by UN experts, the ozone hole could be reduced within four decades. Illustrative photo of Earth taken from the International Space Station in August 2018.
ENVIRONMENT – Finally some good news for the future of the planet. The hole in the ozone layer could be reduced within four decades, and the gradual elimination of chemicals that destroy it is helping to limit climate change, according to a report published Monday, January 9, by a UN Environment commissioned group of experts. However, potential solar geoengineering projects could have undesirable effects, scientists warn.
“The elimination of nearly 99% of banned ozone-depleting substances has helped preserve the ozone layer and has contributed significantly to its recovery in the upper stratosphere and a reduction in human exposure to harmful ultraviolet (UV) rays from the sun,” experts note . If current guidelines remain in place, the ozone hole could close “by about 2066 over Antarctica, 2045 over the Arctic and 2040 in the rest of the world,” they add.
The ozone hole was caused by man-made pollution, particularly chlorofluorocarbons (CFCs), which were once emitted by many refrigerators. In recent decades, however, global cooperation, including 195 countries ratifying the Montreal Protocol, which has greatly reduced CFC use, has given it a chance to recover.
Many uncertainties in geoengineering projects
In 2016, the Kigali Agreement also provided for the phasing out of extremely climate-damaging hydrofluorocarbons (HFCs) in refrigerators and air conditioning systems. Experts already estimate that if the agreement is adhered to, it could reduce global warming by 0.5°C by 2100.
You cannot view this content for the following reasons:
- You have rejected cookies related to third-party content by logging in. You can therefore not play our videos, which require third-party cookies to work.
- You are using an ad blocker. We advise you to disable it to be able to access our videos.
If neither of these two cases applies to you, contact us at [email protected].
However, the latter was also the first to address the potential impact of geoengineering projects on ozone, designed to limit global warming, and warned of their undesirable effects. These projects come up with the idea of intentionally adding airborne particles in the stratosphere to reflect some of the sun’s rays. One of them would be to inject a significant amount of sulfur particles into the upper atmosphere.
These technologies would somehow replicate a volcanic eruption similar to Mount Pinatubo in the Philippines in 1991, which lowered the temperature by 1°C. But ozone levels were degraded in the years that followed, notes John Pyle, co-chair of the scientific panel working on ozone for the UN. Injecting particles into the atmosphere “could lead to a serious drop in ozone levels,” he warns. “There are a lot of uncertainties,” he said.
“The easiest way is to stop giving off gas”
The planet has warmed by almost +1.2°C since the pre-industrial era, which has already led to an increase in heat waves, floods and storms. The international community is committed to limiting this warming to well below +2°C, if possible +1.5°C. However, current policy points to a temperature increase of 2.8°C by the end of the century, which the United Nations says is well above the limits of the Paris Agreement.
Geoengineering projects are sometimes suggested as a solution to save time, but scientists have already warned of the dangers associated with these technologies. A deliberate change in solar radiation, for example, could disrupt the monsoon regime in South Asia and West Africa, wiping out the crops on which hundreds of millions of people depend, according to published studies.
And when the radiation modification stops, “it is very likely that the surface temperature will rise rapidly,” estimates the IPCC. Particle injection over Antarctica has been simulated with mixed results. This would certainly lower global temperature by 0.5°C over twenty years, but the hole in the ozone layer would revert to levels close to those of the 1990s, releasing greenhouse gases into the atmosphere,” said John Pyle. “And it’s difficult.”
See also on The HuffPost:
You cannot view this content for the following reasons:
- You have rejected cookies related to third-party content by logging in. You can therefore not play our videos, which require third-party cookies to work.
- You are using an ad blocker. We advise you to disable it to be able to access our videos.
If neither of these two cases applies to you, contact us at [email protected].